Throughout the 1990s the computers that millions of people worldwide now use in their offices and homes have improved at an amazingly rapid rate, to the point that the power and mobility these devices now bring to their users is indeed breathtaking. In particular, the amount of work they can do has greatly increased while at the same time their size has steadily decreased, the latter to the point that today a capacious and multifunctional computer can be made that is no bigger than a common billfold. But such devices have one major limitation: their keyboard keys are presently so tiny and so close together that it is virtually impossible to enter data into them at typical secretarial speed for any length of time. Indeed, in February 1998 one research manager for a major computer maker (Celeste Baranaski of Hewlett-Packard) said: "Unless some breakthrough is made in keyboard technology, many of these smaller travel keyboards just won't work." And in that same month a journalist (David MacNeill of Pen Computing Magazine) said of present palmtop computers that their "Inappropriate input methods, such as tiny QWERTY keyboards, hobble us in our attempt to enter our information into a device, wasting our time, and even causing physical pain." Indeed, even a slight reduction in a keyboard's width may significantly reduce a typist's speed --as then the keys are arranged differently than the standard spacing at which one may be accustomed to typing.
However, a few inventors have long been aware of this potential deficit of typewriters, computers, laptops, palmtops, calculators, and other alphanumeric or operational input devices that are designed with versatility and mobility in mind. For example, in 1974 George Margolin in his U.S. Pat. No. 3,940,758 described an EXPANDABLE KEYBOARD FOR ELECTRONIC POCKET CALCULATORS AND THE LIKE, in which "a keyboard of familiar layout for a full-size desk top data terminal is organized in three modular portions," which when closed said three modular portions are arranged in a stacked position as shown in FIG. 7 of Margolin's Patent. But it is obvious that Margolin's invention, while reducing the surface or `footprint` area occupied by a standard desktop keyboard by about two-thirds, does so at a sacrifice of triply increasing the keyboard's depth, so that such a device could hardly be carried billfold-style in one's pocket or purse. Then in 1991 Adrian Crissan in his U.S. Pat. No. 5,181,644 described a COMPACT PORTABLE COMPUTER HAVING AN EXPANDABLE FULL SIZE KEYBOARD WITH EXTENDIBLE SUPPORTS, in which the outer quarters of his keyboard comprise "a pair of fold-out flaps containing a portion of the keys" which can be rotated upward and inward so that when in closed position said outer quarters lay flat upon the middle half of the keyboard. But this arrangement also considerably increases the parent units depth by the thickness of its folded-over portions, as is obvious from examination of FIG. 1 of Crissan's Patent. A number of other patented keyboards (see esp. Classes 400/88 and 400/682) have their keys arranged in ways that slide to the side or open to the front in various ways, but none of them truly reduce the footprint size of the parent unit as do the two above-cited Patents, nor do they simultaneously allow the parent unit to achieve a billfold size in all dimensions as does the disclosed invention.